Lithium-inorganic electrolyte cells are capable of providing high energy densities at ambient temperature. These cells employ a lithium anode, a solution of a highly soluble lithium salt such as lithium tetrachloroaluminate in an oxychloride solvent such as phosphorous oxychloride, thionyl chloride or sulfuryl chloride as the electrolyte and a high surface area carbon black cathode. Such an electrochemical cell is disclosed and claimed in Ser. No. 364,575. A novel feature of these cells is that the oxychloride serves the dual purpose of being a solvent for the lithium salt and acting as a cathode depolarizer. One of the best known of these lithium-inorganic electrolyte cells is the lithium-thionyl chloride cell which has been demonstrated to deliver energy densities of the order of 250 watt hours per pound at ambient temperature.
A difficulty encountered, however, with the carbon black cathodes of the lithium thionyl chloride cells is that while they show slight polarization at low discharge rates, they suffer from excessive polarization at high discharge rates.
It has recently been suggested in Great Britain patent application No. GB 2,003,651A, to L. R. Giattino, published Mar. 14, 1979, that the lithium-thionyl chloride cell could be benefited by adding copper to the cell. The difficulty with copper as the additive, however, is that copper is unstable in the electrolyte and partially goes into solution and is deposited on the lithium anode. This deposition decreases the shelf life of the cell as well as causing a worsening of the voltage delay.